Magnetron



Dec. 14, 1.94.8.

R. C. SC HM l DT MAGNETRON Filed Jan. 9,' 1945 Mmm Patented Dec. 14,y 1948 .UNITED STATES PATENT @ENCE MAGNETRON `Robert Schmidt, Newton, Mass., assgnor to v Raytheon Manufacturing Company, Newton,

' Mass., a corporation of Delaware Application January 9, 1945, Serial No. 572,035

more particularly to those ofy small dimensions and relatively low power,l p

One object of therpresent invention is to provide a device ofthe aforesaid general type which v can be produced at relatively low .cost vand which can be used to advantage in radar transmitter circuits or as a local yoscillator in radar receiving circuits and under other situations Where space and weight may bedetermining factors.

Another objectof the present invention is to provide an electron discharge device of the general type referred to having a compact structure andarrangement ofthe parts and'which is self-contained. y r

These and such other aims and objects of the invention as may hereinafter appear vwill be best understood from the following description, taken in connection with the accompanying drawing of one embodiment of the invention.

In the drawing:

Fig. 1 is a vertical section on line- I-I of Fig. 2 of an electron discharge device. incorporating one illustrative embodiment of the invention;

Fig. 2 is a horizontal section on linek2--2 of Fig. l;

Fig. 3 is a vertical. section online 3--3 of Fig. 2; and l Fig. 4 is a horizontal section on line 4-4 of Fig. 1.

The illustrative embodiment ofthe invention shown in the drawing comprises an anode structure consisting of a cylinder 2 having a central Wall 4 projecting from its inner surface, said wall being provided with a central circular aperture 6 to the walls of which are soldered a plurality of radially disposed, suitably spaced, plates or arms 23. Said cylinder 2 and its integral Wall 4 will preferably be made of copper and said plates 8 may be conveniently stamped out of a sheet of highly conductive copper. The inner ends of said plates or arms 8 form anode faces Ill which constitute electron receiving portions and cooperate with a cathode I I having its active portion I2 supported substantially centrally of and coextensive with said anode faces. pieces I4 and I6 are provided at opposite sides of said aperture S and concentrically with the latter and extend into the open ends of said cylinder 2 and into proximity with said anode arms. Said anode structure is supported by electrically conductive rods I8 which are sealed through porcelain seals 20 (only two of which are shown) in said wall 4, the ends being soldered in flangesl Pole,

4 Claims; (Cl. Z50-2.7.5)

, 2 22 and 24 of said pole pieces I4 and I6, respectively. Headers 26 and 28 of steel or other suitable magnetic rnetal are soldered to the two ends, respectively, of va cylinder 30 of electrically conductive non-magnetic metal, such as copper, and

which possess a relatively high coefficient of ther- Y mal conductivity. Said headers thus form with said` cylinder 3B an envelope containing all the parts so far described and which can be evacuatedthrough a pipe 32 Vwhich is then sealed. v

Leaving the ends of the anode cylinder 2 open and enclosing the cathode structure in the larger.

envelope constituted by the copper cylinder 3i) and the two headers 26 and 28 provide increased radiation surface to cool the anode; It will also be noted that the above described arrangements4 of the dii-ferent parts provide a very compact and light device requiring relatively little space.

The flange 24 of pole piece I6 is spot-Welded torr said header' 28, the other header 2S being slightlyv The active portion I2 of said cathode can be coated with an electron emissive substance, such as oxides of the alkaline earth metals. Said cathode ts tightly in an electrically non-conductive nipple 35 inserted in the lower end of a bore 38 extending centrally through said pole.

piece I8 and in alignment with a similar bore 40 in the pole piece I4, and the upper end of the cathode is received in said bore 40 which is of less diameter than said bore 38 in order to fit the cathode which is thus securely centered and electrically connected to said pole piece I4, said cathode being provided with a small longitudinal rib '4I which ts in a slot 43 in the Wall of said bore 4D. Said pole piece I4 may be copper plated to'increase its conductivity. The heater wire 34 extends axially of the cathode, its upper end being connected to the inner surface of the cathode and its other end to a conductor 44 connected in turn to a lead-in conductor 46. From said pole piece I4 the heater wire circuit continues through the rods I8 and the header 26 to the lead-in conductor 4l. The anode lead-in conductor is shown at 49 sealed through said header 28^ see Fig. 3). v

A cylindrical magnet 48 for exciting the pole pieces I4 and I6 may be iitted around the copper cylinder 30 and may thus form a part of the structure forming the object of the present inventon. The result is a complete self-contained compact device.

If the above described electron discharge device be energized and the pole pieces M and I6 excited by said magnet, oscillations will be generated in said device which may be led out through a suitable coaxial line by means of a coupling loop 50 extendingvinto the anode structure above the.

space of a resonator cavity between'two of said anode arms 8. One end of said coupling loop 50 is connected to the inner end of a tubular struc" ture comprising pipes 52 and 58, and the other end of said loop 59 is connected to a conductor` 54 which extends axially of said two pipes S12-,and

58 and is sealed through a porcelain seall car. ried by said header 23, said conductor 54-thus` forming with said pipes 52 and 58 a coaxial line through which the high frequency'oscillations generated by the device may be conducted to any:

suitable utilization circuit. To keep said conductor 54 centered in the pipe 58, insulating mae terial 5l may be provided in said pipe between said conductor and the walls of said pipe.

Each pair of anode arms 8 forms with the portion of the wall 4 between them an oscillating,

A capacitance'exists' tory' work for the measurement of frequencyk wherever ultra-short Waves are concerned, more particularly micro or centimeter Waves. The device is very compact, thus requiring little space, and2 can be produced at relatively low cost.

I am aware that the presen-t invention can' be embodied in other speciiic formsv without departing rfrom the spirit 'or essential attributes thereof, and I therefore desire the presentA de'- scription to be considered in all respects as illus-v tr-ativev andunot restrictive, reference being had to Y theappendedclaims ratherV than to the aforesaid description to indicate the scope of the invention'.v

What is claimed is:

1. An electron-discharge device comprisingr. a. cathode; an anode structure, including'a plurality" of' cavity resonators, spacedV from andv surround-1 L The conductive path' 4. ing said cathode; opposed pole pieces at opposite ends of said cavity resonators; an hermetically sealed envelope enclosing said cathode, said anode structure, and said pole pieces; and means, carried by said pole pieces independently of and spaced from said envelope, supporting said anode structure.

2. An electron-discharge device :comprising: a cathode; an anodestructure, includingk a' plurality of cavity resonators, spaced from and surrounding said cathode; opposed pole pieces at opposite ends of said cavity resonators; an hermeticalli7 sealed envelope enclosing said cathode, said anode structure, and saidpole pieces; means, carried by said-pole piecesindependently of and spaced from saidenvelope, supporting said anode structure; and a cylindrical magnet surrounding said en- Velope.

3, Anrelectron-discharge device comprising: a cathode; an anode structure, including a plurality of vcavity resonators, spacedirom and surrounding said cathode; opposed pole pieces disposed at opposite endslof said cavity resonators; a supportingv member extending4 between, saidA pole pieces and. passingthrough saidanode structure; and. means, carried by 'saidanodeI structure, insulatedlyv supporting said.Y anode structure from said supporting member.

4. An electron-discharge device comprising: a cathode; kan anode structure, includingva plurality of cavity resonators, spaced from` and surrounding said cathode;` opposed pole piecesv disposed at oppositel ends of. saidl cavity resonators; an electricallyfconductive A rod Vextending between said .pole pieces `and passing through said anode.

structure; and an insulator, carried by saidanode structure .an-d, engaging. said,.\rod,i and. supporting said anode structure from said rod. Y

ROBERTO. SCHMIDT.

' REFERENCES CITED The following references are of record in the iilerof" this patent:`

UNT'IlEllDr STATES PATENTS Number Name.. Date 2,063,242 Samuel Dec. 8, 1936A 2,404,212 Bondley 2---- July 16, 1946 2,416,714 Pierce Mar. 4, 1947-- FOREIGN PATENTS Number. Country Date 509,102'n Gre'atBritain. July 11, 1939 

